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Superconductivity Induced by Oxygen Doping in Y 2 O 2 Bi
Author(s) -
Cheng Xiyue,
Gordon Elijah E.,
Whangbo MyungHwan,
Deng Shuiquan
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201701427
Subject(s) - superconductivity , antibonding molecular orbital , doping , atomic orbital , oxygen , condensed matter physics , high temperature superconductivity , crystallography , materials science , chemistry , physics , quantum mechanics , electron
When doped with oxygen, the layered Y 2 O 2 Bi phase becomes a superconductor. This finding raises questions about the sites for doped oxygen, the mechanism of superconductivity, and practical guidelines for discovering new superconductors. We probed these questions in terms of first‐principles calculations for undoped and O‐doped Y 2 O 2 Bi. The preferred sites for doped O atoms are the centers of Bi 4 squares in the Bi square net. Several Bi 6p x / y bands of Y 2 O 2 Bi are raised in energy by oxygen doping because the 2p x / y orbitals of the doped oxygen make antibonding possible with the 6p x / y orbitals of surrounding Bi atoms. Consequently, the condition necessary for the “flat/steep” band model for superconductivity is satisfied in O‐doped Y 2 O 2 Bi.